The gas check seat is a critical sealing surface on the entrance end of gun tube chambers and is ground concentric with the chamber diameter. Previous procedures require overhead crane handling of the gun tube to bring the gun tube to the grinding machine, positioning the tube so that the chamber diameter runs concentric with the axis of the machine, and upon completion of the grinding operation, removing the tube from the machine and moving it to another station.
The concept of the portable grinding machine comprising the present invention eliminates overhead crane handling and moving of gun tubes to a specified machine tool. It also eliminates the need of indicating the true center of the tube chamber, since the portable machine when positioned on the gun tube automatically picks up the true axis of the chamber. The entire grinding operation may be performed in a benching area where numerous gun tubes could be positioned on racks. The portable grinding machine would be handled by a small jib crane and loaded on a specified tube. After grinding the seat the machine could be unloaded from the tube, moved to the next tube in line and the sequence started again.